The present status of biological control of Xanthium (Compositae)     

G. M. Baloch  M. A. Gani 《国际虫害防治杂志》2013,59(2):154-159

Abstract

The economic threshold level of the mustard aphid, Lipaphis erysimi (Kaltenbach) was determined on the radish seed crop, var Punjab Sufed. Spraying oxydemeton methyl at 300 g a.i./ ha, was monitored at arbitrary set aphid levels from 25 to 150 aphids/plant. The maximum cost benefit ratio (1: 13.1) was achieved at an aphid level of 50 per plant, requiring three sprays. Spraying in the middle of February was the most crucial, as delay of 7 days from this stage resulted in significant decreases in yield in the fixed spray schedule and at the 75‐aphid level.  相似文献   

Are road verges corridors for weed invasion? Insights from the fine‐scale spatial genetic structure of Raphanus raphanistrum     

A Barnaud  J M Kalwij  C Berthouly‐Salazar  M A McGeoch  B Jansen van Vuuren 《Weed Research》2013,53(5):362-369

Raphanus raphanistrum (Brassicaceae) is considered amongst the world's worst agricultural weeds. We address critical issues in its management by studying the pathway of colonisation at local scales. For this, we assessed the small‐scale spatial genetic structure of 231 samples collected from three different sites across the Cape Floristic Region, South Africa, using 11 nuclear microsatellite markers. Although natural pollen and seed dispersal were expected to be restricted, we found no significant relationship between genetic and geographical distance within sites. Instead, our results suggest that R. raphanistrum had colonised new habitats via jump dispersal, rather than through natural diffusive dispersal at local scales. We did not find evidence for road verges as dispersal corridors, as evidenced by a lack of isolation‐by‐distance at local scales. Instead, the absence of spatial genetic structure suggests that R. raphanistrum had rapidly spread throughout its current range, possibly facilitated by human‐mediated actions. Management plans addressing containment or suppression of the weedy species R. raphanistrum (and possibly other weedy species) should take the high degree of connectivity between distant geographical localities into account.  相似文献   

不同播期对萝卜杂交种种子质量和产量的影响   总被引：1，自引：0，他引：1  

麻继仙  木万福  杨长楷  李思武  但忠  何璐 《黑龙江农业科学》2013,(11):65-67

为了在云南开发萝卜杂交种子生产基地,以雄不育系和自交不亲和系为萝卜亲本的试材,进行不同播期的生产试验,研究萝卜各处理间的生长期、种子产量和质量等方面的差异。结果表明：播期与生长量呈正比,不同播期对开花期没有明显的影响,但对萝卜种子的产量和质量有显著影响,10月15日播种生产出的萝卜种子的产量和质量最好。  相似文献   

蓝花子自交、远缘杂交结实率和集团选择效果的研究     

吴建华 《中国油料作物学报》1991,(2)

10个蓝花子品种单株套袋自交均表现自交不亲和性,结实率为0;7个蓝花子品种群体套帐自交或品种内杂交,均有不同程度的结实株率和单株结角率。外地品种高州白花与云南8个地方品种正反交,全部获得较高的结实率,正反交间差异不大;与10个甘蓝型油菜品种正反交,结实率≈0;此外与5个白莱型油菜品种、5个芥菜型油菜品种和4个其它类型品种正反交,全部未获得角果。蓝花子的育种以集团选育方法效果为最佳,已选育出5个品系(型)。  相似文献   

萝卜收获机振动松土铲参数的优化   总被引：6，自引：5，他引：1  

付威  陈海涛  坎杂 《农业工程学报》2011,27(11):46-50

为了确定萝卜收获机振动松土铲的关键参数,利用偏心连杆式振动装置进行松土试验,以机器行走速度、松土铲激振频率和振幅、铲入土角、铲刃倾角作为试验影响因素,土壤孔隙度为响应指标,并采用二次正交旋转回归试验设计,建立了响应指标与各影响因素之间回归数学模型。通过Design-Expert 6.0软件对试验参数进行优化,确定机器行走速度0.64?m/s、激振器频率2?Hz、振幅14.38?mm、铲入土角25.72°、铲刃倾角39.68°为最优参数组合,此时土壤孔隙度为50%～60%,该研究为研究和设计萝卜收获机提供依据。  相似文献   

中国萝卜皮色遗传的初步研究   总被引：8，自引：0，他引：8  

何启伟  赵双宜 《山东农业科学》1997,(2):4-9

通过对中国萝卜（ＲａｐｈａｎｕｓｓａｔｉｖｕｓＬ．ｖａｒ．ＬｏｎｇｉｐｉｎｎａｔｕｓＢａｉｌｅｙ）不同皮色试材的杂交，Ｆ１、Ｆ２自交，研究了皮色遗传表现。初步结果表明，皮部绿色（即绿皮）依不同杂交组合，可能有不同的遗传模式，即可由１对基因控制，也可由２对连锁的基因或独立分配的基因对控制。若为连锁的２对基因控制时，它们还受到细胞质基因组（可能主要是质体基因组）的互作，表现出明显的偏母遗传现象。皮部红色（即红皮）似有３对独立遗传的基因控制，这３对基因还有相互作用，其中１对可能与绿色控制基因连锁。这样，红皮与绿皮试材杂交时，参与遗传的基因可达４～５对，它们之间出现复杂的相互作用，而使Ｆ２代出现暗紫、洋红、绿色、紫绿等众多不同颜色。其中有的基因还可能影响到肉质色的遗传，使暗紫色Ｆ２代个体自交，Ｆ３代分离出少数紫皮红心萝卜，将其再自交，则能分离出绿皮红心萝卜，从而在实验过程中证实和重演了绿皮红心萝卜的起源。  相似文献   

春秋季萝卜生长中肉质根木质素含量变化研究   总被引：2，自引：0，他引：2  

李寿田  汪隆植  周健民  娄平  龚义勤 《西南大学学报(自然科学版)》2001,23(2):174-177

对春秋季萝卡生长过程中肉质根的本质素含量变化进行了研究。结果表明,春季木质素含量变化与秋季不同。春季,从破肚期到定桩期木质素含量变化不定,定桩期后木质素显著增加。秋季,从破肚期到定桩期再到露肩期,木质素含量变化不大,露肩期的木质素含量有所下降,采收期以后,木质素含量显著增加。春季萝卡除秋魁青外,其他品种在露肩期前均低于秋季的木质素含量,采收期后,春季萝卡肉质根中的木质素含量高于秋季,这表明,春季萝卡在生长期肉质根的木质化速度要比较季的大。木质素含量变化在红皮萝卡（水萝卜、大红袍）和白皮萝卡（短13、特早30天）之内存在显著差异。  相似文献   

10%氯噻啉可湿性粉剂防治萝卜蚜虫田间药效试验   总被引：2，自引：0，他引：2  

徐燕  徐茜  余鸿燕 《广西农业科学》2007,38(3):282-284

2006年在重庆万州进行10%氯噻啉可湿性粉剂防治萝卜蚜虫田间药效试验,结果表明,在萝卜蚜虫发生期,用10%氯噻啉可湿性粉剂100、200、300g/hm2剂量喷雾防治,药后1d的平均防效分别为90.7%、97.7%、99.0%,药后7d的平均防效分别为84.0%、95.6%、97.5%,均优于对照药剂25%乐.氰乳油400mL/hm2处理的防效,持效期达7d以上。从防治效果及经济成本考虑,建议10%氯噻啉可湿性粉剂防治萝卜蚜虫以施药量100～200g/hm2、喷液量600kg/hm2为宜。  相似文献   

Biofumigant Biomass,Nutrient Content,and Glucosinolate Response to Phosphorus     

Bradford D. Brown  Roger C. Gibson  Brad Geary  Matthew J. Morra 《Journal of plant nutrition》2013,36(4):743-757

Information on biofumigant-green manure vegetative biomass, nutrient, and glucosinolate content sensitivity to phosphorus (P) is lacking for species used in potato and sugarbeet production. Therefore, available P effects on field-grown condiment yellow mustard (Sinapis alba, cv. IdaGold) and oilseed radish (Raphanus sativa, cv. Colonel) were evaluated (2001–03). Low soil P was generally more limiting to radish foliage P concentrations or uptake than to the mustard, suggesting inherent differences in their ability to access and accumulate P. While radish P and S concentrations increased with higher P, concentrations in mustard were either unaffected or reduced. Foliage P concentrations were more closely related to biomass of radish (r² = 0.46) than mustard (r² = 0.11). Mustard exceeded radish in biomass and S accumulation. Phosphorus effects on glucosinolates producing ionic or isothiocyanates were relatively insignificant. These biofumigants differ appreciably in their ability to access and accumulate P, but P effects on nutrient content or glucosinolates were minor.  相似文献   

萝卜花药愈伤组织诱导及褐变因素初探   总被引：1，自引：0，他引：1  

王绍辉  高遐虹  程继鸿  杨瑞  赵金芳  邓伟 《中国农学通报》2008,24(11):350-354

以萝卜为试材,研究了不同激素配比、供体基因型、光照与温度以及蔗糖浓度对花药愈伤组织诱导的影响,同时比较研究了花药愈伤组织褐变过程中几种抗氧化酶活性变化。结果如下：P403在2.0mg/L 2,4-D+1.0mg/L 6-BA+2.0mg/L KT的MS培养基中愈伤组织的诱导率最高,愈伤组织开始褐化的时间晚,抗氧化酶的活性较高;同时进行低温预处理、高温预培养和初期暗培养的协同效果较任何一种单独处理好;6%的蔗糖浓度有利于愈伤组织的诱导。  相似文献